Using glucose is not the same as being treatable by avoiding sugar
The body regulates glucose in the blood and can make it from other nutrients. Cutting out sweets, or even cutting out carbohydrates, does not simply switch off a cancer's energy supply.
Cancer Research UK and the National Cancer Institute do not support sugar restriction as a proven way to treat cancer. There is no basis for promising that a sugar-free diet will make a tumour shrink or improve survival.
Does that mean diet does not matter?
No. Diet matters for general health, and frequently having more energy than the body needs can contribute to weight gain. Excess body fat is associated with several cancers. This is different from saying that one sugary food caused an individual's cancer.
Fruit, milk and other ordinary foods also contain sugars. A list of foods containing sugar is not a list of foods that someone with cancer must avoid.
During treatment, the immediate problem may be eating enough
Poor appetite, nausea, swallowing difficulties or taste changes can make meals difficult. Restrictive rules may remove foods that someone can still manage and increase the risk of inadequate nutrition.
If you are eating less or losing weight unintentionally, ask your team for a dietetic assessment. Advice may differ from general advice about weight management. People with diabetes may also need a plan that accounts for treatment, medicines and changing food intake.
See eating difficulties and weight changes during treatment for more detail. Do not stop prescribed treatment, change diabetes medicines or start fasting on the basis of a social-media claim.
A useful question for your team
Ask: “Given my treatment, symptoms and weight pattern, what should I prioritise with food?” That is more useful than trying to follow a universal cancer diet.
General information only. This article cannot recommend a diet for your individual circumstances.
